This invention relates to an improved ski design and more particularly to an improvement in the efficiency of Downhill skis, Giant Slalom skis, Slalom skis and Recreational Alpine skis.
The present ski design has developed over the years. The two key factors which affect the performance of a ski are the "camber" which is the upwardly bowed bottom surface and the "side camber" or "side cut" in which the forward end and rear end of the ski are wider then the center or waist of the ski.
Clement, U.S. Pat. No. 2,258,046 issued Oct. 7, 1941 illustrates an early ski which incorporates camber. Beerli in U.S. Pat. No. 2,210,794 issued June 6, 1950 illustates th concept of "side camber".
Unfortunately snow conditions and ski terrain are not uniform and vary dramatically. Thus skis are required to perform on conditions ranging from ice, hard packed powder, powder, corn snow, broken crust, etc. Skiing is also a difficult learned skill in which the ability of the skier is an important factor.
There have been many modifications to the design of skis over the years to improve their performance. Most of these have been within the state of the art while other more novel designs have been patented.
Some examples of the former are:
1. The design of the side camber (side cut) has been varied to optimize the turning radius of the ski. The designs are noticeably different in some downhill and slalom skis.
2. The placement of the boot has been moved forward and/or backward from the usual position on the ski.
3. The stiffness of the ski has been varied not only of the entire ski but also to have different degrees of stiffness between the forward portion of the ski and the rearward portion of the ski.
4. The degree of curvature and height of the "camber" (upward bowed bottom surface) have also been modified usually in relation to the stiffness and length of the ski.
Some examples of the latter are:
1. U.S. Pat. No. 4,377,297 which describes an alpine ski with a special modified side cut which has a bulge under the boot area to apply more edge pressure at this point of the ski during a turn.
2. Other patents showing variation in side cut are Austrian Patent No. 173,373 and German Patent 643,186.
3. Canadian Pat. No. 1,148,680 is for a reverse camber (bottom bowed) ski which is suited for beginner skiers as it is easier to turn.
4. U.S. Pat. No. 4,487,426 describes a ski with a reverse or relatively no camber combined with a convex or modified convex side camber.
5. A number of novel ski designs have been developed such as U.S. Pat. No. 4,085,947 which describes a rearward controlled snow ski which is basically a short ski with the rearward position of the ski (behind boot) being 20% of the ski length.
Another significant factor to improve the capabilities of the skier and thus the performance of the skis has been the "forward lean" built into the ski boot. This has allowed the skier to shift his weight as required during turns while making it easier (due to the cantilever effect) to maintain his position relative to the fall line of the ski slope. Unfortunately standing on skis with this boot on level ground or walking causes discomfort to the skier.
The sport of skiing requires a high degree of skill from the participant. To control the skis and their direction and maintain balance on a wide range of snow conditions the skier must shift his weight in many directions, apply edging and apply other forces to his skis which appropriately apply them to the ground (ski slope). As it is only through the skis that the desired forces can be applied, the ski design is critical to the sport.